Thanks for reaching out and providing those details! I'm sorry for the inconvenience here. There is no official size limit, however our team is aware that some users have faced this issue. I will open a ticket on your behalf so that our Support team can dive a bit deeper on this issue with you.

We do know that people are seeing issues somewhere around 5000 px. If you are syncing your artboards using Craft Sync at the 2x, which is the Craft default, you would be breaking the 5000 px mark. I suggest trying to sync at 1x.

Please let me know if there's anything else I can help you with. Otherwise, please look for a message from our Support team soon.